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Bioenergetics of the VO₂ slow component between exercise intensity domains.

ABSTRACT: During heavy and severe constant-load exercise, VO₂ displays a slow component (VO_2sc) typically interpreted as a loss of efficiency of locomotion. In the ongoing debate on the underpinnings of the VO_2sc, recent studies suggested that VO_2sc could be attributed to a prolonged shift in energetic sources rather than loss of efficiency. We tested the hypothesis that the total cost of cycling, accounting for aerobic and anaerobic energy sources, is affected by time during metabolic transitions in different intensity domains. Eight active men performed 3 constant load trials of 3, 6, and 9 min in the moderate, heavy, and severe domains (i.e., respectively below, between, and above the two ventilatory thresholds). VO₂, VO₂ of ventilation and lactate accumulation ([La^-]) were quantified to calculate the adjusted oxygen cost of exercise (AdjO_2Eq, i.e., measured VO₂?-?VO₂ of ventilation?+?VO₂ equivalent of [La^-]) for the 0-3, 3-6, and 6-9 time segments at each intensity, and compared by a two-way RM-ANOVA (time?×?intensity). After the transient phase, AdjO_2Eq was unaffected by time in moderate (ml*3 min^-1 at 0-3, 0-6, 0-9 min: 2126?±?939?2sc was explained by a prolonged shift between aerobic and anaerobic energy sources in heavy (VO₂?-?VO₂ of ventilation: ml*3 min^-1 at 0-3, 0-6, 0-9 min: 3769?±?1128?-]: 452?±?254?2sc in severe.

SUBMITTER: Colosio AL

PROVIDER: S-EPMC7476983 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Bioenergetics of the VO2 slow component between exercise intensity domains.

Colosio Alessandro L AL Caen Kevin K Bourgois Jan G JG Boone Jan J Pogliaghi Silvia S

Pflugers Archiv : European journal of physiology 20200714 10

During heavy and severe constant-load exercise, VO2 displays a slow component (VO2sc) typically interpreted as a loss of efficiency of locomotion. In the ongoing debate on the underpinnings of the VO2sc, recent studies suggested that VO2sc could be attributed to a prolonged shift in energetic sources rather than loss of efficiency. We tested the hypothesis that the total cost of cycling, accounting for aerobic and anaerobic energy sources, is affected ...[more]

PMID: 32666276

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Bioenergetics of the VO₂ slow component between exercise intensity domains.

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Bioenergetics of the VO<sub>2</sub> slow component between exercise intensity domains.

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